Various systems have been proposed to display a message in a vehicle to be read by the driver of another vehicle. Typically, these systems include a static back-lit display in the rear window which is illuminated when the brake peddle is depressed or at the option of the driver. Other units allow the driver to select from a limited number of messages to be displayed or input a message, via a keyboard, into the system. To display the message, the driver's attention may be directed away from the road, possibly creating a dangerous situation. Additionally, it would be helpful to provide a message to other vehicles as to changes of direction or forewarn of road conditions up ahead.